What is Contract?
What is a contract? Learn the legal definition, how contracts work in freelance and B2B relationships, the essential clauses every freelancer should understand, and how invoices relate to contracts.
What Is a Contract?
A contract is a legally binding agreement between two or more parties that creates mutual obligations enforceable by law. In the context of freelancing and B2B services, a contract establishes the rules of engagement: what work will be done, how much will be paid, when payment is due, who owns the intellectual property, and what happens if either party fails to deliver. Contracts exist on a spectrum of formality — from a simple email exchange agreeing to terms, to a multi-page Master Services Agreement governing a multi-year engagement. Written contracts are strongly preferred in professional relationships because they provide clear, documented evidence of what was agreed to.
The Four Elements of a Valid Contract
Contract law is built on four foundational elements: 1. Offer — One party makes a clear proposal describing what they will do (or refrain from doing) and what they want in return 2. Acceptance — The other party agrees to the terms of the offer, either explicitly (by signing) or implicitly (by beginning performance) 3. Consideration — Something of value is exchanged between the parties — payment for work, services for compensation, goods for money 4. Legal Capacity — All parties must have the legal ability to enter into a contract (not a minor, not under duress, not mentally incapacitated)
Common Types of Contracts in Freelancing
Master Services Agreement (MSA) A broad agreement that establishes the overall legal relationship between a client and freelancer. It typically covers IP ownership, confidentiality, payment terms, and general legal provisions. Individual projects or engagements are then governed by Statements of Work (SOWs) issued under the MSA. Statement of Work (SOW) A project-specific document that defines the scope, deliverables, timeline, and pricing for a specific engagement. An SOW sits under an MSA and is used to authorize individual purchases (often via PO). Freelance Contract A contract specifically for a discrete freelance engagement — typically covering a single project or a set period of work. It combines the key elements of an MSA and SOW in a single document. Retainer Agreement An ongoing contract in which a client commits to paying a set amount per month (or per period) for a defined set of services. The retainer guarantees the freelancer's availability; the client gets dedicated access. Fixed-Price Contract The freelancer agrees to deliver specific work for a set total price. The scope is defined upfront; payment is tied to milestones or completion. Time and Materials Contract The client pays for the freelancer's time at an agreed hourly or daily rate, plus reimbursable expenses. More flexible for projects where scope is uncertain.
Essential Contract Clauses for Freelancers
Scope of Work — Precisely defines what work is being performed. Critical for avoiding scope creep. Payment Terms — When payment is due (e.g., Net-30 from invoice), what triggers payment, and what happens for late payment. Intellectual Property (IP) Ownership — Who owns the work product once created and paid for. Freelancers should understand the difference between "work made for hire" and retaining ownership until paid. Kill Fee — A fee the client pays if they terminate the contract before completion. Protects freelancers from lost income on cancelled projects. Confidentiality (NDA) — A clause requiring both parties to keep certain information private. Standard in many corporate freelance engagements. Termination Clause — Under what conditions either party can end the contract, and what compensation is due upon termination. Limitation of Liability — Caps the maximum damages one party can claim against the other. Freelancers should negotiate reasonable caps. Revision Rights — How many rounds of revisions are included, and what additional fees apply for revisions beyond that.
Contracts vs. Invoices — How They Relate
A contract establishes the terms of the relationship; an invoice is the instrument of payment under that relationship. Think of it this way: a contract is the rulebook, and an invoice is how you call a play from that rulebook. Each time you bill a client, your invoice operates under the framework established by your contract — payment terms, late fees, IP provisions, and all.
The Bottom Line
A contract is a mutual, legally binding commitment between parties. For freelancers, a well-drafted contract is your single most important business protection — defining what you'll deliver, when you'll be paid, and what happens when things go sideways. Key Takeaways: 1. A contract requires offer, acceptance, consideration, and legal capacity to be valid 2. Common freelance contract types: MSA, SOW, freelance contract, retainer, fixed-price, time-and-materials 3. Essential clauses include: scope, payment terms, IP ownership, kill fees, confidentiality, and termination 4. A PO is narrower than a contract — multiple POs can operate under one master contract 5. Eonebill helps you manage contracts and invoices in one place Protect your freelance business with professional contracts and invoices — Try Eonebill Free View Pricing → | Glossary Home → | Home →